Here's a quick bit from Jeffrey Zeldman that plays into my contention that email (along with blogs, etc) is a key cog in the remediation of manuscript culture and genres:

But when I say HTML mail still sucks, I don’t mean it sucks because support for design in e-mail today is like support for standards in web browsers in 1998.

I mean it sucks because nobody needs it. It impedes rather than aids communication.

E-mail was invented so people could quickly exchange text messages over fast or slow or really slow connections, using simple, non-processor-intensive applications on any computing platform, or using phones, or hand-held devices, or almost anything else that can display text and permits typing.